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V � November 24, 1997 Harding Lawson Associates 39960 1 Margaret Lagorio, Supervising REHS San Joaquin County Public Health Services Environmental Health Division Page 2 delivery pipeline and the courtyard tanks (concrete vaults) and sump (concrete). Three angled soil borings were drilled in the vicinity of the courtyard tanks and sump designated NSA-1, NSA-2 and NSA-3. The locations of these borings are shown on the attached Plate 1. Two soil samples were collected from each borehole. The borings were drilled to an approximate depth of 20 feet (borehole depth)below ground surface (bgs). Samples collected from approximate 10 and 20 feet within the borings were submitted from each boring for chemical analyses. Samples were analyzed for total petroleum hydrocarbons, quantified against a diesel standard (TPH-d), total recoverable petroleum hydrocarbons (TRPH), and benzene, toluene, ethylbenzene and xylenes (BTEX). No BTEX was reported. TPH-d was only detected in the shallow samples from NSA-1 and NSA 2, with a maximum concentration of 730 milligrams per kilogram (mg/kg) found in NSA-2. TRPH was detected in each sample, with concentrations ranging between 110 and 13,000 mg/kg, with the exception of the deeper sample (20.5 feet bgs) from NSA-3. In October/November 1993, the courtyard tanks and sump were abandoned in-place by Resna Industries Inc.by removing remaining contents, cleaning, and backfilling with a cement slurry. Prior to backfilling, soil samples were collected through the bottom of the tanks and sump through holes placed in the concrete bottoms. A total of six soil samples were collected and submitted for TPH-d and BTEX. TPH-d was found to be present in low to moderate concentrations in all but one of the samples collected from beneath the tanks and sump. The highest recorded concentration of TPH-d (600 mg/kg) was detected at the eastern end of the sump. This sample was also analyzed for soluble TPH-g, TPH-d and BTEX. Leachable TPH-d was reported in the extract at 1.3 milligrams per liter. (mg/L). It is not known if the laboratory used deionized water or an acid for this analyses. No groundwater was encountered during these activities. PROPOSED SCOPE OF WORK This proposed scope of work includes the tasks described below. Task 1.0: Preparatory Activities Boring permits will be secured from the PHS/EHD prior to drilling activities. Proposed locations will be marked in white at least 48 hours prior to drilling, and Underground Services Alert notified. A private utility locator will also be used to clear borehole locations. Prior to commencement of work, a site specific Health and Safety Plan (HSP) will be modified. During all field work, procedures outlined in the site specific HSP will be followed. The Health and Safety Plan is intended to identify and mitigate the hazard exposure encountered by onsite personnel. The plan will include provisions for site access control, worker training and medical monitoring requirements, worker personal protection, onsite and offsite monitoring, personnel decontamination, and contingency planning. All personnel conducting activities at the site will be properly trained in their specific assigned work functions. They will be familiar with the operation of equipment required for assigned tasks and will be capable of mitigating physical hazards associated with the operation of the equipment. :a